AMYLOLYTIC ACTION OF SALIVA. 



417 



Second Series. The following experiments are selected to 

 illustrate how an increase in the amount of neutral saliva 

 added may modify the influence of a definite proportion of 

 acid, presumably owing to a combination of its proteid with 

 the latter. The relatively weaker inhibitory action of com- 

 bined acid is thus demonstrated. 



TABLE D. 



Period of digestion, 10 minutes. 



In Experiment I, 3.3 c.c. saliva were added to Tube 2, whereupon the mix- 

 ture was digested, and gave a color comparable to No. 4 of the color scale. 

 In Experiment II, it required three successive additions of 3.3 saliva to bring 

 about digestion. 



TABLE E. 

 Period of digestion, 10 minutes. Temperature, 17 C. 



At the end of ten minutes 0.3 c.c. saliva was again added to Tubes 2 and 

 3. Tube 2 still gave an acid reaction, while Tube 3 digested at once, and at 

 the end of ten minutes gave with potassium hydroxide a color reaction 

 slightly weaker than that obtained with Tube 1. 



In the following protocols the effect of the reverse process, 

 namely, diminishing the amount of neutral saliva added when 



27 



